Vehicles such as electric vehicles (EVs) and plug-in hybrid vehicles (PHVs) have a rechargeable battery serving as a power storage apparatus for storing electric power that should be supplied to a traveling motor. As one such rechargeable battery, for example, known is a rechargeable battery having a stacked structure in which positive electrodes, negative electrodes, and separators insulating the electrodes, are stacked alternately to form an electrode assembly. However, accomplishing the stacked structure requires manufacturing steps of sequentially stacking the positive electrodes, the negative electrodes, and the separators, that is, a great number of stacking steps. This prolongs the production cycle time and thus decreases productivity. To solve this problem, a technique has been devised to decrease the number of the aforementioned stacking steps and thus improve productivity for rechargeable batteries by, for example, accommodating positive electrodes in bag-shaped separators in advance (see Patent Document 1).
As described in Patent Document 1, a bag-shaped separator is configured by welding protruding sections of opposed first and second sheet-like separators (separator members) to each other. The bag-shaped separator accommodates a positive electrode and a tab of the positive electrode projects from the bag-shaped separator. In stacking steps of bag-shaped separators and negative electrodes, edges of the bag-shaped separators and edges of the negative electrodes are positioned by being brought into contact with a positioning member. These edges should be located on the bottom of an electrode assembly. The stacking steps of bag-shaped separators and negative electrodes include a step of conveying the bag-shaped separators to a position at which the steps of stacking the bag-shaped separators with the negative electrodes will be performed. The bag-shaped separators are conveyed after the edges of the bag-shaped separators are brought into contact with the positioning member and the bag-shaped separators are arranged at predetermined positions.